Preparation of s-(1-alkenyl) phosphorodithioates



3,021,352 Patented Feb. 13, 1962 3,021,352 PREPARATION OF S-(l-ALKENYL)PHOS- PHORODITHIOATES Bernard Miller, Stamford, Conn., assignor toAmerican Cyanamid Company, New York, N.Y., a corporation of Maine NoDrawing. Filed Sept. 2, 1960, Ser. No. 53,613

Claims. (Cl. 260-461) The present invention relates to novelS-(l-alkenyl) phosphorodithioates represented by the general formula:

C=CHS1L (031): R in which R is a hydrogen, a lower alkyl or an arylradical and R is lower alkyl, and to novel methods for the preparationthereof.

Phosphorothioate compounds of the which have the general groupingpresent invention,

find utility as pesticides and, particularly, as insecticides.

Advantageously, they are prepared by admixing an inert organlc solvent,and in any desired order 0,0,0,O-tetraalkyl dithiophosphonothioatehaving the representative structure: I r

wherein R is a lower alkyl radical, and approximately equimolarquantities of a metal vinyl compound conforming to either structure:

/ C H: C HMgX O=CHM in are, for instance:

0,0,0',O'-tetramethyl dithiophosphonothioate,

0,0,0,O'-tetraethyl dithiophosphonothioate,

0,0,0,O'-tetra-n-propyl dithiophosphonothioate,

0,0,0',O-tetrabutyl dithiophosphonotbioate,

0,0,0,O'-tetrapentyl dithiophosphonothioate, homologs and isomersthereof.

Illustrative metal vinyl compounds contemplated herein are:

Vinyl magnesium bromide, Vinyl magnesium chloride,

Styryle magnesium bromide, Propenyl magnesium chloride, Butenylmagnesium bromide, Isobutyl magnesium chloride, Vinyl lithium,

Vinyl sodium,

Vinyl potassium,

Propenyl lithium,

Butenyl lithium,

A pentenyl lithium.

. Suitable inert solvents include:

Hexane,

Cyclohexane,

Dioxane,

Ether,

Xylene,

Toluene, and equivalents thereof.

The compounds of the present invention are highly active insecticidesand may be used as sprays in organic solvents, as emulsions in water orother non-solvents, or on solid carriers, such as talc, clays,diatomaceous earths and the like. Such amounts of inert carrier may beused as are customarily employed in the art. However, the activepesticidal compound is present in amounts ranging from about 0.1 percentto about 5 percent based on the weight of the inert carrier.

Inorder to facilitate a further understanding of the invention, thefollowing examples are given primarily for purposes of illustrating morespecific details thereof. It is to be understood, however, that thescope of the invention is not to be deemed limited thereby, except asdefined in the claims. Unless otherwise noted, parts given are for theaforementioned reaction by weight.

EXAMPLE 1 Preparation of 0,0-dz'ethyl, S-(fi-Slylyl) phospkorodithiouteTo a solution or" 10 parts of 0,0,0',O'-tetraethyldithiophosph'onothioate (0.027 mol) in 10 parts by volume of ether areadded 50 parts by volume of 0.69 molar styryl magnesium bromide (0.035mol). After stirring for twenty minutes, the reaction mixture is dilutedwith ether, poured into water, washed with dilute hydrochloric acid anddried over magnesium suitate. The, solvent is evaporated and the productdistilled in vacuo to obtain a yield of 4.6 parts or 59 percent based onthe theoretical amount of desired product which is a yellow liquidhaving an index refractive (N equal to 1.582 to 1.583 and analyzing inpercent as follows:

Calculated for PS O C H C, 49.90; H, 5.94; 3, 22.20; P, 10.73. Found: C,50.35; H, 6.20; S, 22.45; P,'l0.98.

EXAMPLE 2 Preparation of 0,0-dimethyl S-(fi-styryl) plzosphorodithiom'eRepeating Example 1 in every material detail except0,0,0,O'-tetramethyldithiophosphonothioate is substituted for the0,0,0,O-tetraethyl dithiophosphonothioate reactant. 0,0-dimethylS-(fi-styryl) phosphorodithioate is recovered in good yield and having arefractive index I 3 (N equal to 1.6190, analyzing in percent asfollows: Calculated for PS O C H C, 46.4; H, 5.03; S, 24.6; P, 11.89.Found: C, 40.6; H, 5.10; S, 25.5; P, 12.27.

EXAMPLE 3 Preparation of 0,0-dimethyl, S-vinyl phosphorodithioate To asolution of 0,0,0',O'-tetramethyl dithiophosphonothioate (9.5 parts) in25 parts by volume of ether are added in a suitable reaction vessel 25parts by volume of 1.5 N vinyl magnesium bromide within 60 seconds. Thereaction mixture is then diluted with ether, poured into water, washedwith dilute hydrochloric acid and dried over magnesium sulfate. Thesolvent is evaporated and the product is distilled in vacuo to obtain3.2 parts or 57.8 percent based on theoretical amount of desired lightyellow liquid product having a refractive index (N equal to 1.5331 andshowing the following analysis for PS O C H in percent:

Calculated: C, 26.05; H, 4.92; S, 34.7. Found: C, 26.38; H, 5.20; S,35.03.

EXAMPLE 4 The phosphonothioate reactant in the above Example 3 issubstituted by 0,0,0',O'-tetraethy1 dithiophosphonothioate and theprocedure followed in every material detail. A good yield of0,0-diethyl, S-vinyl phosphorodithioate (62 percent of theory) isobtained. The desired compound has a refractive index (N equal to 1.512to 1.514 analyzing in percent as follows:

Calculated for PS O C H C, 33.95; H, 6.17; P, 14.59; S, 30.19. Found: C,33.85; H, 5.51; P, 14.85; S, 29.74.

EXAMPLES Preparation of 0,0-diethyl, S -I-butenyl phosphorodithioate To10.45 parts of 0,0,0,O'-tetraethyl-dithiophosphonothioate (0.028 mol)having the structure:

0,O-diethyl-S-naphthylvinyl phosphorothioate, 0,0-diethy1-S-isopropenylphosphorothioate, 0,0-dimethyl-S-n-propenyl phosphorothioate,0,0-diethy1-S-l-butenyl phosphorothioate.

As above stated, the compounds of the present invention are highlyactive and efiective insectides. To demonstrate the marked degree ofinsecticidal activity, each of the products of the above examples aredissolved in a solvent therefor comprising 65 percent acetone and 35percent water at a concentration of 0.1 percent based on the weight ofthe compound. The solution is sprayed on Nasturtium aphids and theresults of the tests are presented in the table below.

TABLE I Compound Percent Kill 0,0-Diethyl, S-(B-styryl)Phosphorodithioate 98 0,0-Diethyl, S-vinyl Phosphorodlthioate 1000,0-Dimethyl, S-(B-styryl) Phosphorodithioate 100 0,0-Dimethyl, S-vinylPhosphorodithloate 100 I claim: 1. A method forpreparing,'phosphorodithioates represented by the general formula:

wherein R is a radical selected from the group consisting of loweralkyl, monocyclic aryl and dicyclic aryl and R is a lower alkyl radical,which comprises: reacting in substantially equimolar amounts 2. metalvinyl compound selected from the group consisting of:

A where R is as defined above, X is. a halogen atom and M is an alkalimetal,

with a dithiophosphonothioate of the structure:

where R is a lower alkyl radical.

2. A process according to claim 1, in which the metal vinyl compound isstyryl magnesium bromide.

3. A process according to claim 1, in which the metal vinyl compound isstyryl magnesium chloride.

4. A process according to claim 1, in which the metal vinyl compound isbutenyl lithium.

5. A process according to claim 1, in which the dithiophosphonothioateis 0,0,0',O-tetraethyl dithiophosphonothioate.

References Cited in the file of this patent UNITED STATES PATENTS2,266,514

Romieux Dec. 16, 1941 2,767,206 Whetstone Oct. 16, 1956 2,864,740Diveley Dec. 16, 1958 2,864,741 Diveley Dec. 16, 1958 FOREIGN PATENTS784,985 Great Britain Oct. 23, 1957 UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent N0a 3,021,352 February 13 1962 BernardMiller It is hereby certified that error appears in the above numberedpatent requiring correction and that the said Letters Patent should readas corrected below.

Column 1, lines 30 to 32 the formula should appear as shown belowinstead of as in the patent:

Signed and sealed this 26th day of June 1962 (SEAL) Attest:

ERNEST w. swwra DAVID LADD Attesting Officer Commissioner of Patents

1. A METHOD FOR PREPARING PHOSPHORODITHIOATED REPRESENTED BY THE GENERALFORMULA: